you need to take collett out and clean and lube with never seize lube ,make sure that there is not any shot between fingers of collett . it just takes a little time and patience . there will be other ideas on here too ,this has been covered alot on here . hope this helps Jeff

What Jeff said! nothing wrong that a good enema cleaning won't fix......not the easiest to do, take an old toothbrush and solvent for starters and loosen the plastic and crud up....you can lift the tube out that the primers drop through by pushing it up from the bottom with a finger, it is just held there by gravity, then you can see the fingers and clean them and make sure there is no shot or debris stuck in between, lube the outer area with never-seize after cleaning and it'll work nice and smooth.
To remove the plastic buildup I have tried the same stuff that melts out wads from choke Tubes, called "Shooters Choice Shotgun and Choke Tube cleaner".....Frank C

Every time I've experienced this dilemma, I've found a crushed lead pellet between a couple of fingers. It's just enough of a stoppage for the dropping hull for it to fail to get to the bottom before the sizing occurs.....breakemall....Bob Dodd

I bought up a dental pick to clean those tough to get to spaces on my 9000H. It has an off-set head which allows the pick to get at each space fairly easy. A piece of stuck shot will flatten out to where it looks like a powder flake once it's dis-lodged, I then use canned air to blow out the crud. Works great on my machines! Hap

Before you disassemble the collet to clean/check for damage/lead pellets, check the shell lifter. The shell lifter should be clean and dry. If it has any lube on it, that can cause the shell lifter to drop too slowly or not at all. If it is dirty or covered with grease or oil, clean it and clean the area of the collet that the shell lifter drops through. That will usually take care of a slow hull drop or no hull drop.

sometime the loaders that are in great shape are the most problems. I have a few 650s one looks like hell paint worn everywhere a bit rusty in some places BUT absolutely cranks out great shells! another I have looks brand new but a hack really screwed it up. Apparently something got jammed in it. well there is a few bent parts, personally I think it took a trip off a truck or long flight of stairs. looks great until you start to use it. I find a really good cleaning and lube goes a long way into getting loaders on track. I have redone a few loaders. Find a lot of crud up inside the precrimp and final crimp tube enough to definitely affect the out come of the shell. I recently picked up a 600jr I asked the guy how many loads he ran through it. laughing he said "well for 10 years I loaded a shot ATA about 8000rnds min a year plus hunting and friends so ill say 150,000. it works great!

All good advice above has been said. Here is one though that was a new one to me. I have a customer's Grabber that I am working on. I discovered that the shell lifter is activated by a flat bar on the bottom which is pushed up by the rod in the front of the machine. If I tilt the Grabber just far enough to make the flat bar get out of alignment, it won't lift the shell all the way out and tries to crush the brass on the hull. Move the flat bar back into alignment, and everything returns to normal. Sunday, will try to limit the bar to stay in the correct place everytime. Anybody else had this problem? Anybody read the MEC Secrets book and did they learn anything? IMHO Omaha